1. Field of the Invention
The present embodiments relate generally to a delivery system for an endoluminal prosthesis having an expandable graft.
2. Description of Related Art
Using stent grafts to treat aneurysms or similar defects is common in the medical field. Stent grafts are deployed by accessing a vasculature with a small incision in the skin and guiding a delivery system to the target area. This intraluminal delivery is less invasive and generally preferred over more intrusive forms of surgery.
The stent grant can be placed against the vessel wall in the area of the defect to close off the defect and provide patent fluid flow through the area of the defect, thereby allowing the defect to heal itself while limiting or substantially preventing blood loss through the vessel wall.
Methods for delivering a stent graft are well known in the art, and involve guiding the stent graft over a guide wire or similar structure until the graft reaches the target location. During the delivery, the stent graft, including a cannula therein, is in a compressed state with a diameter that is smaller than the diameter of the graft in the deployed state. The smaller diameter allows the graft to be delivered while limiting the trauma to the patient, with the graft typically delivered through the use of a catheter, as is known in the art.
Once the catheter with the graft is delivered to the target site, the catheter can be withdrawn back along the guide wire toward the surgeon, leaving the graft in place. The stent is then released from its compressed state by typically withdrawing a trigger wire in the case of a self-expanding stent. After withdrawing the trigger wire, the self-expanding stent will expand outwardly into contact with the luminal wall.
Alternatively, the stent can be expanded by using a balloon therein, which can be inflated to force the diameter of the stent outward and into engagement with the luminal wall.
Once expanded, the stent is generally limited in its ability to reduce the diameter. This is because the purpose of the stent is to provide outward pressure on the luminal wall to remain in place and treat the vascular defect.
However, there are instances where the surgeon may desire the ability to reduce the diameter of the stent after it has at least partially expanded, such as an instance where the stent needs to be repositioned along the vasculature, either due to initial misplacement or discovery of an additional defect adjacent the target site.
In the event the stent graft is not adequately positioned, the surgeon may be required to deliver an additional stent graft to the same target area to sufficiently treat the defect, adding time and material to the procedure and resulting in increased trauma to the patient.
Therefore, there is a need to provide a stent graft that can be at least partially expanded and subsequently compressed to allow the surgeon to reposition the stent graft after initial expansion.